Telephone system



May 29, W23.

31,456,536 E. H. CLARK TELEPHONE SYSTEM Filed Dec. 4, 1919 Margina/ Fate-suited May 2%, 19230 caravan stares insane @ATENT @FMQEQ EDGAR H. CLARK, OF NEW YORK, N. Y., 'ASSIGNOR TO WESTERN ELECTRIC COMPANY,

INCORPORATED,

OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE SYSTEM.

Application filed Beceniber c, 1919. Serial No. 342,412,

To all whom it may concern:

Be it known that I, EDGAR H. (Joann, a citizen of United States, residing; at New York, in the county of New New York, have invented certain new and useful Improvements in Telephone Systems, of which the following is a full, clear, concise, and exact description. v

This invention relates to telephone exchange systems and more particularly to systems involving the use of selective signaling apparatus for operating the signal- 7 ing devices on subscribers lines.

i called line number.

In telephone systems in which a transition is taking place from the manual method of establishing connections to the use of antomatic switches for accomplishing that purpose, it is desirable that certain ofiices be equipped with'both call indicator trunks and manual connecting circuits at final operators positions. A call indicator is arranged in the usual manner in common to the in;

coming trunks from an automatic oflice, and may be assigned b the final connecting operator to any trun at her position on which a call appears. If party lines are to be served, an indication is first produced on the indicator to inform the operator of the Also a ringing selection condition is automatically set up on apparatus individualto the trunk to determine the application of the proper kind of ringin current to operate the called subscribers bell on the party line when the operator com letes the connection.

Vi hen, however, a call s extended from a distant manual ofice over one of the manual connecting circuits at the operators position, it is necessary to provide means whereby the operator may cause the application of the proper character of current to ring the called substation hell on the party line. It; has been common practice to equip manual circuits of this character each with a set so that when a call is completed by any of actuation of the keys' individual to that circuit applies the necessary ringing current. Where, as in systems of the character above outlined, it is necessary to assemble at the same 'oper'ators trunks and manna connecting circuits, the expedience of securing a uniformity of the acts pertormedb the operator in handling both types, of ca 8 becomes obvious. MorenianuaI circuits be York, State of osition call indicator over, it is desirable that the construction and operation of the ringing equipment of the made to closely conform with that required for call indicator trunks. By. this means the conversion of manual connecting circuits to call indicator trunks may be obtained with comparatively few'changes and alterations.

Accordingly, it is the object of this invention to provide ringing selection devices common to a group of connecting circuits at an operators position by means of which the operatormay control the application of a lurality of kinds of ringing current to su scribers lines. 1

A feature of the invention relates to the provision of a common key set, arranged to be associated with any of a plurality of connecting circuits by manual means individual to each circuit, and by means'of which keys a plurality of relays are operable in variable combinations to set up and maintain a plurality of ringing selection conditions. L

Other features and advantages of this invention will become apparent from a consideration of the following description and appended claims.

n the drawing there is indicated at the left of the vertical broken line an A operators sition in a manual office, from which position outgoing connecting circuits lead to a distant otiice. Fig; 1 shows a cord circuit used by the A operator in extending connections to the outgoing connecting circuits. Fig. 2 shows in detail the incoming end of one of these connecting circuits terminating at ;a B operatofls position in the distant oflice, together with a party line to which connections are extended by the B operator. This figure also shows a portion of a second one of the incoming connecting circuits from the distant A operators position.

According to the system in which this invention is embodied, a final connecting or B operators position is equipped with a plurality of connecting circuits incoming from a distant cities by means of which the B operator completes the extension of calls to party lines ap caring in multiple'j-acks at er position. 'set'of ringing selectlon keys is provided in common to all the connecting circuits at the B oper'ators position tor the purpose of determining the proper character of ringing current to be applied to a sets of relays, when once-energized in the combination determined by the actuation of the common keys, are locked up and remain energized independently of said common keys. When the plug of the connecting circult over which the call has beenextended is inserted in the jack of the called line the common set of ringing keys is automatically disassociated from the connecting circuit and is then free to be associated with other circuits. The ringing selection relays .now

serve to cause the application in the proper manner of one of two. sources of ringing current to the party line to operate the bell at the called substation to the exclusion of the bells at the other substations.

In the drawing there are shown only the detailed circuits of one of the four subscribers stations on the party line. The other three substations are illustrated diagrammatically. In order to secure the necessary number of ringing combinations with the use of two sources of ringing current of diiierent character, the call bells at two of the subscribers stations are connected from the tip side of the line to ground. The-bells at the other two' subscribers stations are connected from the ring side of the line to ground. These bells are constructed to operate on the biased principle, a hell on each of thetip and ring sides of the line responding only to positive current and the remaining two bells on-the tip and ring side responding only to negative current.

In the following detailed description of the operationbf the system disclosed, it 'will be assumed that a call, elther originatin at, or having been extended from other ofices to the A operators position, illustrated at the left of the vertical broken line in the drawing, is to be further extended to a party line served through the B operators position. It will further be consideredthat the callingparty wishes to converse with the subscriber at substation 200 on the party line. When the call is initiated, the A operator responds to the same in the usual mannerby inserting answering plug 101 in the jack (not shown) of the subscribers line or of the trunk circuit incoming to her position, as; the case may be. .Upon the number of the'called line and the stations designation being com-' incense municated to her, the A, operator converses with the B operator in the called office by means of the'usual order wire (not shown).

In her conversation with the B operator the A operator communicates to her the number of the called line and the designa= tion of the wanted station thereon, and also -requests the assignment of a .connectingcircult for the purpose of extending this connection. The A operator is then notified that a connectingi circuit, such as the one shown in detail in ig. 2, is idle and may be taken for use. Accordingly the A operator insorts the plug 102 of her cord circuit in the jack 107 of the assigned connecting circuit leading to the B operators position in the called oflioe. Upon the insertion of the plug 102 in 'ack 107 a circuit is closed from battery t rough supervisory lamp 105, relay 103, sleeve of plug 102, sleeve of jack 107 to ground/ Lamp 105 is illuminated by the current flowing in this circuit. Relay 103 becomes energized and completes a circuit. from ground through the upper right-hand winding of repeatingcoil 106, front contact and armature of relay 103, tip of plug 102, tip of jack 107,

outer right-hand armature and contact ofrelay 208, upper left-hand winding of repeating coil 231, left-hand winding of relay 204 to battery and. ground. Rela 204 completes a circuit from ground t rough its armature and contact, winding of relay 205 to battery and ground. Relay 205 by energizing closes a. circuit from ground through its inner right-hand armature and front contact, innenleft-ha'nd armature and contact of relay 228, back contact andrighthand armature of relay 207, assignment lamp 209 to battery and ground. The illumination of lamp 209 in this circuit advises the B operator that the connection has been extended to the assigned trunkin the calling oflice. The B operator now depresses an assignment key 206, individual to the connecting circuit. Key 206 establishes a circuit from ground throu h itsclosed contact, right-hand winding 0 relay 207, outer left-hand armature and contact of relay 228-.to battery. and ground. Re lay-207 becomes energized and closes a substltutelocking circuit for itself through both of its windings in series and its innerleft-hand armature and contactto ground.'

The operation of relay 207 disconnects the assignment lamp 209 from the armature and front contact of relay 205 and connects it to the "interrupter 211. The interrupter 2111 causes the intermittent illumination and ex tinguishment of lamp 209 so long as relay 207 remains energized. Relay 207 also closes a circuit at its outer left-hand arm 'ture and contact for the relay; 208. Relay 208 by attracting its right-hand armature opens the ahovetraced circuit for relay 204 permitting relays 204 and 205 to retract ing keys 210, 220,

conductors ing circuit extended.

The operator having learned that a conversation is desired with the subscriber at substation 200, depresses the key 230 to set up a condition for the application of the 208, which latter relay,

f so

jack 227 of t is called line.

lay'224 to proper character of ringing current to cause the operation of the bell at that substation. The actuation of key 230 completes a circuit from ground through the left-hand contact of said key, conductor 233, inner left-hand armature and contact of relay 208, conductor 234, winding of relay 212 to battery and ground. Relay 212 energizes and completes a circuit for itself from battery through the winding and contact and inner right-hand armature of said relay, conductor 236 to ground at the contact and outer left-hand armature of relay 215. Relay 212, therefore, remains energized independent of the common ringing key 230.

The operator then seizes the plug 226 of the connectin circuit and inserts it in the The insertion of plu 226- in the jack 227 causes a circuit to be c osed from ground through the winding of relay 225, sleeve of jack 227, sleeve of plug 226, conductor 237, winding of rebattery and ground. In parallel to this circuit a circuit is also closed for relay 228. Relay 224 at its right-hand armature closes the tigconductor 238 of the connecting circuit. lay 224 also closes a circuit from battery through the winding of relay 212, contact and inner right-hand armature ofrelay 212, contact and inner lefthand armature of relay 224 to ground. This .circuit serves to maintain the energization of relay 212 independently of the relay 228, which also energizes in parallel with relay 224, opens the above traced circuit for relay 207. Relay 207, therefora'releases its armatures and opens the circuit of lamp 209, whereby said lanip ceases to flicker. Relay 207- at the same timeopens the energizing circuit of relay by releasing its armatures, disassociates the common ringing keys 210, 220, 230 and 240 from the'connectin% circuit.

clay 208 at Relay its right-hand armatures completes the tip and ring sides of the connecting circuitthrough to the repeating coil231. Belay 204, therefore, becomes energized again inthe circuit ,above traced through its left-hand winding to ground at the repeating coil in the A o erators cord circuit, shown in Fig. 1. he ener- 204 in turn causes the gization of relay energization of relay 205 as described. Re-

221, winding of relay 223 to ground.

- ringer lay 228 also completes a circuit from batk tery through the disconnect lamp 217, contact and right-hand armature of relay 228, contact an, armature of relay 214, back contact and right-hand armature of rellly lay 223 attracts its armature and connects the tip and ring conductors 238 and 239 tothe lefthand armatures of relay 212. Relay 221 is also included in a branch parallel to the circuit just traced but does not energize since it is shunted out by the path leading through the contact and armature of relay 214. The disconnect lamp 217 does not receive sufficient current in series with relay 223 to become illuminated. As soon after the energization of relay 205, which takes place as shown following the insertion of the plug in the jack, as a conducting segment of the pick-up interrupter 216 makes engagement brush, a circuit is closed for the pick-up relay 215. This circuit leads from battery through the interrupter 216, normally closed right-hand contact of relay 215, winding of said relay, contact and left-hand armature of relay 205, contact and outer leithand armature of relay 224, to ground. Relay 215 energizes and locks up in a circuit closed through its inner right-hand armature and makerbefore-break contact. With the ringing relay 223' and the pickup relay 215 both energized, the ringing circuit is completed for the application of negative current to the tip side of the called line. This circuit may be traced with its cooperating from the ringing source 219 through the v inner armature of relay 223, conductor 238,

front contact and right-hand armature of relay 224, tip of the plug 226, tip of the jack 227 over the tip side of the party line, winding of relay 241 at the desired substation, and then returning by way of the ring side of the party line, ring of the jack 227, ring of plug 226, conductor 239, outer armature and front contact of relay 223, outer left-hand armature and front contact of relay 212 to ground. Relay 241 responds to the first impulse of current over this circuit, and by attracting its armature closes a circuit from the ringing source 219 over the tip side. of the line directly to ground through the 242. The bell 242 operates in response to cu'rrentflowing in this circuit to the exclusion of the bells at the other substations on the party line.

When the called subscriber responds by removing his receiver.

a low resistance path is closed through the windings of biased res from the switchhook,

switchhook contacts which permits the energization of the marginal relay 214 in .series with the source of ringing current, Relay. 214 by attracting its armature opens the short circuit around the winding of relay 221. Relay 221, therefore, energizes in series. with the disconnect lamp 217 and relay 223. Relay 221 at its right-hand armaof relay 223,'conductor 239, ring of plug 226, rin of jack 227 over the loop of the called SlfilStfltlOn, tip of jack 227, tip of plug 226, right-hand armature and front contact of relay 224, conductor 238,.inner armature and back contact of relay 223, upper right hand winding of repeating coil 231 to ground. The supervisory relay 222' energizes .in this circuit and completes a circuit rom battery through the lower right-hand windingof the repeating coil 106 in the A operators cord circuit, winding of super visory relay 104, ring of plug 102, ring of jack-.107, inner right-hand armature and contact of relay 208, lower left-hand winding of repeating coil 231, right-hand windin of relay 204, armature and contact of re ay 222, left-hand armature and contact of relay 221 to ground. Relay 204, therefore, remains energized by means of circuits closed through both its windings and the windings of repeating coils 231 and 106.. The supervisory relay 104 by attracting its armature closes a direct circuit from battery through the winding of relay 103 to ground at the sleeve of jack 107. This circuit shunts out the supervisory lamp 105 which becomes extinguished to advise the A operator that the called subscriber has answered.

If, after the called subscriber has replaced his receiver on the switchhook' and before the B operator has removed plug 226 from the called line jack 227, the operator wishes to rering the called subscriber, she may do so by momentarily disconnecting the plug 102 from'jack 107. The removal of plug 102 from jack 107 o ens the energizing circuit of relay 204. lay 204 in turn causes the deenergization of relay 205. Re-

lay 205' b retracting its armatures closesJi circuit rom batte through disconnect lamp 217, contact an right-hand armature of. relay 228, back contact and outer rightacaasc hand armature of relay 205 to ground. This I direct circuit to ground in series with lamp 217 shunts out the relay 221, which releases its armatures When the plug is again inserted in jack 107, relays 204 and 205 again become energized. The original circuit,'ineluding lamp 217, the back contacts and armatures of'relays 214 and 221, and the windingof relay 223 is thereupon closed. Relay 223 energizes and ringing current is supplied to the called line in the same manner as already described.

en the conversation is finally com pleted and the called subscriber replaces his receiver on the switchhook, relay 222 deenergizes and opens the circuit above traced for the supervisory relay 104 in the A operators cord circuit. Relay 104 retracting its armature removes the shunt'from around supervisory lamp 105. Lamp 105 becomes lighted to inform the operator that the connection is no longer desired. She then withdraws the plug 102 from the jack 107 This opens the circuit throu h the left-hand winding of relay 204. 1elay 204 deenergizes and causes the deenergization of rela-y 205. The above' traced circuit is then completed for the disconnect lamp 217 to ground at the back contact and outer righthand armature of rela 205. The B 0 erator observing the stead y illumination 0 the, disconnect lamp knows that the conversation has been completed and proceeds to rescribed connection, it was assumed that the party at substation 200 was desired, the bell at this substation being-responsive only to negative currenton' the tip side of the line. it been required to ring the bells at any of the other three substations, the operator would have actuated the proper one of the common keys to set up the cond-ition of applying the' necessary character of ringing current .to the line. For example, to apply positive current to the ring side of the line she would depress key 220. The actuation of this key' closes a circuit from ground through its closed contacts, conductor 232, .outer left-hand armature and contact of relay 208, conductor 235, through the winding of relay 213, to-battery and ground. Relay 213 energizes and locks up in the manner already described in connection with the relay 212. When the plug is inserted in the jack, the relay 213 being energized, itive current is connected to the-rin si e of the line in an obvious manner. 0 apply positive current tothe. tip

side of the line the operator depresses key 240, which causes the energization of both relays 212- and 213. To send negative current over the ring side of the line none of the keys 220, 230 and 2&0 need be operated.

Should the operator discover after having actuated one of the keys 220, 230 or 240 to set up a given ringing condition that she had inadvertently selected the wrong key, the improper ringing condition may be erased by the depression of key210. The

operation of key 210 closes circuits from battery over either conductors 234 or 235 or both, contact and inner right-hand armature of either relay 212 or relay 213 or both, dependent upon the combination of these relays energized, to ground at the contact and outer left-hand armature of relay 215. These circuits shunt out whichever of the relays 212 or 213 happen to be energized to permit their release. The operator then proceeds to operate the proper key to agaln set up the ringing condition.

it will be observed that when ringing current is to be applied to the tip side of a party line, the ringing circuit for the application of the necessary kind of current leads through the outer right-hand arn'iature and contact of relay 215. The reason for this expedient is to prevent the closure of the ringing circuit until after the plug has been fully inserted in the jack. Should the sleeve of the plug make contact with the sleeve of the ack during the period that the tip of the plug is in contact with the ring of the jack, a brief impulse of ringing current would be momentarily transmitted over the ring side of the line were the ringing circuit completed at this time. To obviate th s the ringing circuit is made dependent, as explained, upon the operation of relay 215. Relay 215 cannot become energized until the sleeve relay 224 has been energized and until the pick-up interrupter 216 has advanced one of its metallic segments into engagement with the cooperating brush. This feature greatly reduces the probability that a ringing current will be inadvertently sent over the ring side of the line when calls are being made to subscribers whose bells are connected to the tip side of the line.

If while the connecting circuit, shown in detail, is in use the operator is advised that a second call is awaiting her attention, she assigns another idle connecting circuit, such as the one illustrated. within the broken rectangle shown in the drawing. by depressing the assignment key 2% individual to this connecting circuit. The relay 245 is operated to cause the operation of relay 246 in the manner above described. Relay 246 causes the association of the common key set i and the operator proceeds to set up the ringing combination necessary to signal the desired party on the called line.

What is claimed is:

1. In a telephone system, an operators position, a plurality of connecting circuits thereat, switches for extending saidconnecting circuits, a set of'keys common to said circuits, an individual key for each circuit for associating the common keys with said circuits, a plurality of sources of current, a plurality of relays. means controlled by said common keys for operating a variable number of said relays to connect any of said sources of current to one of the connecting circuits, and means responsive to the operation of one of said switches for disassociating the common key set from the connecting circuit.

2. in a telephone system, position, a plurality of connecting circuits thereat, a manually operable switch individual to each circuit for extending such circuit, a set of keys common to said connecting circuits, individual keys, one for each circuit for associating the common key set with any one of said circuits, a plurality of sources of current of different character, a plurality of relays, means controlled by said common keys for operating a variable number of said relays to connect any of said sources of current to one of said connecting circuits, and means responsive to the operation of one of said switches for disassociating the common key set from the corresponding connecting circuit.

3. In a telephone system, an operators position, a plurality of connecting circuits thereat, a set of keys common to said circuits. individual keys, one for each circuit for associating said common keys with any one of said circuits, a plurality of sources of current, a plurality of relays, means controlled by the common keys for operating a variable number of said relays to connect any of said sources to one of said circuits, means for maintaining the connection of one of said sources of current to the connecting circuit independent of said keys, and means controlled by the connecting circuit for disasseciating the common keys therefrom.

i. In a telephone system. an operators position, subscribers lines terminating in jacks at said position, a group of connecting circuits terminating in plugs at said position for extending connections to said lines, a set of keys common to said circuits. keys individual to the connecting circuits for as" sociating said set of keys with a desired one of said connecting circuits, a plurality of sources of current, a plurality of relays. means responsive to the actuation of said common keys for operating a variable number of said relays to connect any of said sources to said circuit. means for maintaining the connections of said sources of current to the connecting circuit independent of said keys, and means responsive to the an operatorstill tit)

insection of the plug of said connecting circuit in the jack of a subscribers line for disassociating said set of common keys-from the connecting circuit.

5. In a telephone s stem, an operators position, subscribers line s terminating in acks at said position, a group of trunks terminating in plugs at said position for extending connections to the subscribers lines, an individual assignment key for each of said trunks, a set of keys common to said trunks, means responsive to the actuation of one of said amignment keys for associating the common set of keys with the corresponding trunk, a plurality of sources of ringing current of different character, a set of relays individual to said trunk, means con- :trolled by said common set of keys for operating a variable number of said relays, means controlled by said relays for variably connectin any of said sources of current to said trunk, means for maintaining said relays in their operated condition independent of said common keys, means responsive to the insertion of the plug of said trunk in the jack of a subscriber s line for applying said sources of current to said line; and means responsive to the insertion of said plug in the jack for disassociating the common key set from said trunk.

6. In a telephone system, an opcrato'rs position, a plurality of connecting circuits thereat, each terminating in a manual switch serving to extend said circuits, a set of ringing keys common to said circuits, individual keys, one for each circuit for associating the common keys with any one of said circuits, a plurality of sources of ringing current, a plurality of relays, means controlled by the common keys for operating a variable number of said relays to connect any of said sources to one of said circuits, and means rcsponsive to the operation of one of said manual switches for disassociating the com mon keys from the corresponding connecting circuit.

7. In a telephone system, an operators position, a telephone line, a plurality of connecting circuits at the operators position for extending connections to said line, a set of keys common to said circuit, individual keys, one for each circuit for associating incense said common keys with any one of said circuits, a plurality of sources of current, a plurality of relays, means controlled by the common keys for operating a variable number of said relays to connect any of said sources to one of-the connecting circuits, means for maintaining the connection of said sources of current independent of said keys, means responsive to the connection of a connecting circuit to said line for disassociatin said common keys from such circuit, and means controlled over said line for disconnecting said sources of current from the connecting circuit.

8. In a telephone system, an operators position, a subscribers line, a plurality of connectin circuits at the operators position for extending connections to said line, a set of keys common to said circuits, individual keys, one for each circuit for associating said common keys with any one of said circuits, a plurality of sources of current, a plurality of relys, means controlled by the common ke s 101' operating a variable number of said relays to connect any of said sources to one of the connecting circuits to signal the subscribers line, means for maintaining the connection of said sources of current independent of said keys, means responsive to the connection of a connecting circuit to said line for disassociating said common keys from such circuit, and means operated by the response of the subscriber for disconnecting said source of current from the connecting circuit.

9. In a telephone system, an operators position, a plurality of connecting circuits thereat, switches for extending said connecting circuits, a set of keys common to said circuits, an individual key for each circuit for associating the common keys with said circuits, a plurality of sources of current, means controlled by said common keys for connecting said sources of current to one of the connecting circuits, and means responsive to the operation of one of said switches for disassociating the common key set from the connecting circuit.

In witness whereof, I hereunto subscribe my name this 28th day of November A. D,

EDGAR H. CLARK. 

